Etiologic Agents and Antibiotic Resistance Pattern of Community- and Hospital-Acquired Infections

Background and Objective: Empirical antibiotic therapy of communityand hospital-acquired infections without the knowledge of the common causes and resistance patterns of the infections can lead to the enhancement of antibiotic resistance. Regarding this, the aim of this study was to determine the etiologic agents and antibiotic resistance pattern of communityand hospital-acquired infections. Materials and Methods: This descriptive-analytical study was conducted on hospitalized patients with positive microbial cultures in two hospitals of Hamadan city, Iran, during 2012-2015. The participants were assigned into two groups of communityand hospital-acquired infections after their examination in terms of clinical manifestations. In addition to the common pathogens and their resistance patterns, the patients were examined for the type of interventions and underlying diseases. The data were analyzed in SPSS software (version 20) using the statistical tests. Results: Out of the 818 documented infections, 108 (13.2%) and 710 (86.8%) cases were communityand hospital-acquired infections, respectively. The majority of the positive cultures were respectively observed in the tracheal (62.7%), urinary (23.7%), and blood (9%) samples. Furthermore, the most frequent medical interventions included peripheral venous catheter (71.9%), suction (64.3%), ventilator (59.6%), and urinary catheter (16.5%). The most common etiologic agents of nosocomial infections were Escherichia coli (19.3%), Pseudomonas aeruginosa (18.9%), and Acinetobacter baumannii (16.6%). Regarding the communityacquired infections, the most common etiologic agents included E. coli (19.4%), coagulase-negative staphylococci (18.5%), and Pseudomonas aeruginosa (14.8%). The highest reported resistance among nosocomial infections was related to oxacillin and ciprofloxacin. On the other hand, community-acquired infection showed the highest resistance to vancomycin and ciprofloxacin. Conclusion: As the findings indicated, Gram-negative bacteria are more common in both communityand hospital-acquired infections. In addition, the results were indicative of the enhancement of antibiotic resistance over